All manner and variety of devices or appliances configured for the absorption of such body fluids as menses are of course well known. As a class, these articles ought to possess certain necessary attributes of absorbency, comfort and psychological as well as physiological or physical protection. Desirably, these devices also are characterized as being discreet both during wear and when carried upon the wearer's person in anticipation of use. As will be seen from the ensuing discussion, these objectives are somewhat antagonistic in the sense that attainment of one has heretofore ordinarily necessitated compromising one or more other desirable feature.
The art has offered two basic types of feminine protection device with those objectives borne in mind; sanitary napkins or pads have been developed for external wear about the vulvar region of a user while tampons have been developed for residence within the vaginal cavity and interruption of menstrual flow therefrom. Each offers distinct advantages and, as one would expect, distinct or peculiar disadvantages, which range from psychological impediments and/or concerns to physical discomfiture.
Looking to tampons as such an alternative to sanitary napkins, the same are preferred by a substantial number of women. Offering the ability to intercept menses within the vaginal canal, the disadvantages inhering in sanitary napkins in respect of covers and attachment means are overcome by this approach. That is not to say, however, that tampons afford a superior means of feminine protection for all users. For example, there are many individuals who, for either physical or psychological reasons, are unable to utilize tampons as an effective means of feminine protection. Tampons themselves may be found lacking in terms of construction inasmuch as efficacy relies significantly on the ability of the same to undergo radial expansion upon fluid swelling in order to form a seal or zone of occlusion within the vaginal canal. Failure to do so implies overall failure of the tampon to serve as a reliable protection device.
While there are essentially three types of tampons, plunger, stick and digital, the most preferable type of tampon in the United States is the plunger type. The tubes for the plunger type are either of the disposable or non-disposable variety. During the past several decades, increasing emphasis has been placed upon the ease of disposability of consumer goods after the goods have performed their intended purpose. A paper tampon tube, to be easily disposable must be formed with an adhesive readily soluble in cold water and preferably constructed so that delamination of the tube occurs in a short period of time.
Plunger-type tampons are generally formed in two parts with an outer tube having an inner diameter slightly greater than the outer diameter of the tampon pledget inserted therein. The second part of a tampon inserter means is some type of plunger which operates in cooperation with the tube to expel the pledget. The tubes are generally made of paper products such as cardboard or thermoplastic. Further, thermoplastic tubes generally have an insertion end which forms a hemispherical profile around the leading edge of the tampon to protect it and maintain its integrity during insertion. Commercially available tampons utilizing cardboard tubes, however, generally do not have this type of closure, but rather the leading edge of the tampon extends beyond the tube end. Both thermoplastic and paper derived tubes can be made with a reduced diameter base which can be used for gripping or to better maintain the plunger used for expulsion, or for both purposes.
The ideal tampon tube should be inexpensive, simple to make, easily disposable, attractive and hygienic. Both molded plastic and paper inserter tubes have not been completely satisfactory in meeting these desirable attributes. There are no commercially available tubes molded from thermoplastics that are water disposable or flushable. Furthermore, the relative cost of thermoplastic is substantially greater than tubes which are made from paper or paper products. In addition, thermoplastic molded tubes having a hemispherical shaped leading edge comprising individual arcuate shaped lobes are extremely difficult to mold without providing lobes having sharp edges or flashing, i.e. irregularly shaped burrs of plastic. Such tubes could provide problems when being withdrawn from the vagina. Paper tubes, on the other hand, also have problems. Commercially available cardboard tubes for tampons are generally spirally wound and open at the leading edge which may result in a fiber slough when the tampon is inserted. Such tubes generally have a relatively low beam strength, that is, a low resistance to a radial collapsing of the tube. One example of such spirally wound paper tubes can be found in U.S. Pat. No. 3,764,438, issued Oct. 9, 1973. After the outer tube is formed, the end through which the tampon is ejected may be shaped to have a tapered portion of smaller diameter than the diameter of the tampon. Such tapered portion has a generally round termination with corrugations on slits to form flexible petal portions through which the tampon can be forcibly ejected by the inner telescoping tube. The adhesive for holding the spiral layers together may be water soluble so that the paper tubes may be thrown into a toilet and flushed into the drain pipe. The water soluble adhesive causes delamination of the spiral layers so that the rigid tube structure is quickly softened. The paper is of a type chosen to disintegrate in water. Spirally wound tubes have a relatively low beam strength.
Recent advances in the making of paper tubes by convolutely winding the tubes for greater beam strength are disclosed in U.S. application Ser. No. 446,838 filed Dec. 6, 1982, said application being commonly assigned.
Heretofore, cardboard tampon tubes made from multiple plies of paper have had the same number of plies for both the inner and outer tubes. The outer tube generally requires greater strength and rigidity than the inner tube. Accordingly, when the inner tube has the same number of plies as the outer tube an unnecessary expense is involved.